Fiber Optic Update - A Peek At The Future, A Look At The Past

The beginning of the year is always a good time to reflect on the past and contemplate the future. Except in fiber optics. It is hard to get people to look back, as the last year and a half has been pretty painful for many in fiber. The telecom part of the business has seen markets and companies collapse all over the place, as numerous businesses were founded or expanded to build products for a market that never materialized. Corporate scandals added to the misery.

But in the midst of all this bad news, the premises fiber optic industry did much better than many expected. Sure, it had its bad times, as the “Internet Hotel” concept fizzled with the dot-com collapse and many startups in networking businesses bit the dust. But the emergence of even higher network speeds and the confusion over new copper cabling standards worked to fiber’s advantage. Several vendors said that the premises fiber market was still growing well, and one quoted 100 percent growth from 2000 to 2001.

The growth in Gigabit Ethernet (GbE) use is a major driver in fiber growth. The one-Gigabit standard gained wide acceptance among corporate network users and introduced the inexpensive 850 nm VCSEL laser source and laser-rated multimode fiber to the market. Both these components have shown strong growth and are gaining acceptance in new networks.

The 850 nm VCSEL has such high volume that its cost is now well below that of 1,300 nm LEDs and is approaching the cost of inexpensive 850 nm LEDs. Besides being chosen as one option for the new 10- GbE standard, it is being considered for use in 10- and 100-megabit Ethernet networks, including the recently introduced 100Base-SX standard now using 850 LEDs.

Laser-rated fiber made a slow start after its introduction for use with GbE. Its size, with a 50-micron core, was incompatible with all the 62.5-micron core fiber currently installed, and its extra performance offered only marginal improvement. Most users ignored it because of the hassle of managing two sizes of multimode fiber.

But the new 50-micron fiber offers at least four times the bandwidth of previous 50 micron fibers, making it compatible with upgrades to 10 GbE. It even provides significantly longer (4X) network distances with the low-cost 100Base-SX equipment. Some users still worry about managing two incompatible multimode fibers, but the new laser-rated fibers offer enough advantage to sway many others.

On the connector front, we reported last month that the small form factor connectors have not achieved their lofty sales goals, a consequence of difficulty of installation and high costs. In a paper presented at a conference late last year, one consultant reported failures of 17 percent with the MT-RJs installed in his job, even with factory techs assisting the installers, and said 5 percent failed on the second try. In an industry where yield equals profit, this kind of news is enough to discourage many users from trying new products.

While the United States and Japan were suffering economic woes and not doing a lot of R&D on connectors, a relatively unknown Swiss company, Huber+Suhner, introduced a unique termination system using heat-cured epoxy technology. A handheld tool (made like a Swiss watch, naturally) holds the connector, cures the neat, powered epoxy and cleaves the fiber. A quick air polish finishes off the connector with a total termination time of less than two minutes. Of course, only extensive field experience will tell if it stands up to abuse in the field and produces reliable, cost-effective terminations.

Preterminated cable assemblies continue to grow slowly. Most of these schemes use the 12-fiber MT-style ribbon connector. This connector is convenient, but with vendors quoting up to 1 dB loss, it becomes a weak point in the low-loss links required for Gigabit networks. And designing an exact-length cable plant for a big building is a daunting task for most designers.

In test equipment, premises fiber finally got its own OTDR, optimized for the short distances of these cable networks. Fluke Networks Optifiber has the resolution necessary to troubleshoot LAN cabling, right down to patch-cord lengths.

On the standards front, fiber continues to get more respect in the “568” standards. All the new components are now approved, including the laser-rated fiber, as well as alternate architectures that favor fiber’s distance advantages over copper. The fact that the new 10 GbE standard only offers fiber optic cabling options tells the network and contractor world that fiber is now the one choice for cabling in the future. EC

HAYES is a VDV writer and trainer and the president of The Fiber Optic Association. Find him at www.JimHayes.com.